Washing machine

ABSTRACT

Disclosed is a washing machine. The washing machine includes: a machine housing; a washing tub having an inner tub which accommodates laundry and is rotatable and an outer tub for receiving the inner tub, and being provided inside the machine housing; four supporting members, which are configured to be in a shape of a rod suspended from the machine housing and elastically support the washing tub; and receiving portions, which are mounted at the lower portion of each of the supporting members respectively to connect the supporting members to the washing tub. All the receiving portions are provided at the same height. The length of a pair of front supporting members and that of a pair of rear supporting members are different.

TECHNICAL FIELD

The present disclosure relates to a washing machine.

BACKGROUND

In a washing machine described in the following Patent Document 1, anouter tub is supported by four hanging rods inside a machine frame, awashing and dehydrating tub is rotatably supported inside the outer tub,and a pulsator for agitating the laundry is provided at the bottom ofthe washing and dehydrating tub. The rotational power of a motorattached to a lower surface of the outer tub is transmitted to thewashing and dehydrating tub and the pulsator. A lower end of the hangingrod is fixed to a mounting piece protruding from the bottom wall of theouter tub, and an upper end of the hanging rod is held by a hanging rodreceiving metal that is fixed to a mounting piece protruding inward fromthe machine frame. The vibration of the outer tub in the case of thedewatering process of the washing operation or the like is absorbed by acompression spring that is provided at the top end of the hanging rod asa vibration-proof body.

The washing machine described in Patent Document 1 has the followinghidden danger: when a braking is applied to the rotation of the washingand dehydrating tub to stop the dehydrating process, the outer tub mayvibrate greatly due to the bias of the laundry in the washing anddehydrating tub, and four hanging rods cannot completely inhibit thevibration of the outer tub, causing the outer tub to collide with themachine housing of the washing machine.

EXISTING ART LITERATURE Patent Literature

Patent Literature 1: Japanese Laid-Open Patent Publication No.2001-137592

SUMMARY

The present disclosure has been made based on the above background, andan object of the present disclosure is to provide a washing machinecapable of preventing a washing tub provided in a machine housing fromvibrating and colliding with the machine housing.

The Solution to the Problem

The present disclosure relates to a washing machine. The washing machineincludes a machine housing; a washing tub having an inner tub whichaccommodates laundry and is rotatable and an outer tub for receiving theinner tub, and being provided inside the machine housing; foursupporting members, which are configured to be in a shape of a rodsuspended from the machine housing and elastically support the washingtub; and receiving portions, which are mounted at the lower portion ofeach of the supporting members respectively to connect the supportingmembers to the washing tub. All the receiving portions are provided atthe same height, and among the four supporting members, the length of apair of supporting members and the length of another pair of supportingmembers are different.

In addition, the present disclosure is characterized in that the washingtub is capable of rotating in a manner of crossing with a verticaldirection.

Effect of the Invention

According to the present disclosure, the four support members formed ina shape of a rod suspended from the machine housing are connected to thewashing tub by the receiving portions attached to the lower portions ofthe four support members, respectively, such that the support memberselastically support the washing tub provided inside the machine housing.All the receiving portions are provided at the same height. Among thefour supporting members, the length of a pair of supporting members andthe length of another pair of supporting members are different. Whensuch a structure is adopted, the vibration of the washing tub iseffectively suppressed by the four supporting members when the inner tubof the washing tub is rotating during the dewatering process of washingoperation or when a braking is applied to the rotation of the inner tubfor stopping the dewatering process, thereby suppressing the vibrationof the washing tub and its collision with the machine housing.

In addition, according to the present disclosure, the washing tub iscapable of being rotated in a manner of crossing with a verticaldirection. With a washing machine having the above-mentioned structure,the vibration of the washing tub can be suppressed through the foursupporting members, and thus, the present disclosure can suppress thevibration of the washing tub and its collision with the machine housing.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a left view of a main portion of a washing machine accordingto an embodiment of the present disclosure.

FIG. 2 is a schematic longitudinal sectional view of a main portion anda peripheral portion of a supporting member of the washing machine.

FIG. 3 is a schematic left view of the main portion of the washingmachine.

FIG. 4 is a diagram showing a relationship between an amplitude of thevibration of an outer tub of the washing tub generated along with therotation of an inner tub during the dewatering process and a lengthdifference between a front supporting member and a rear supportingmember.

FIG. 5 is a diagram showing a relationship between an amplitude of thevibration of the outer tub generated along with the termination ofrotation of the inner tub at the end of the dewatering process and alength difference between a front supporting member and a rearsupporting member.

FIG. 6 is a left view of a washing machine in a modified example.

A LIST OF REFERENCE NUMERALS

1: Machine housing; 2: Washing tub; 3: Outer tub; 4. Inner tub; 7:Supporting member; 7A: Front supporting member; 7B: Rear supportingmember; 18: Receiving portion; 100: Washing machine; Z: Up-downdirection

DETAILED DESCRIPTION

The embodiments of the present disclosure will be described in detailwith reference to the accompanying drawings. FIG. 1 is a left view of amain portion of a washing machine 100 according to an embodiment of thepresent disclosure. The up-down direction in FIG. 1 is referred to as anup-down direction Z of the washing machine 100, the left-right directionin FIG. 1 is referred to as a front-rear direction Y of the washingmachine 100, and a direction perpendicular to the paper surface in FIG.1 is referred to as a left-right direction X. The up-down direction Z isa vertical direction. Regarding the up-down direction Z, the upper sideis referred to as an upper side Z1, and the lower side is referred to asa lower side Z2. Regarding the front-rear direction Y, the right side ofFIG. 1 is referred to as a front side Y1, and the left side of FIG. 1 isreferred to as a rear side Y2. Regarding the left-right direction X, thesurface side of the paper surface in FIG. 1 is referred to as a leftside X1, and the inner side of the paper surface in FIG. 1 is referredto as a right side X2.

The washing machine 100 includes a washing and drying machine that has alaundry drying function. However, in the following, the washing machine100 will be described with an example of the washing machine in whichthe laundry drying function is omitted and only the washing operation isperformed. The washing operation includes a washing process, a rinsingprocess and a dewatering process. The washing machine 1 includes amachine housing 1 constituting an outer shell of the washing machine.Inside the machine housing 1, a washing tub 2 that is, an outer tub 3and an inner tub 4 constituting the washing tub 2, a motor 5, atransmission mechanism 6 and a supporting member 7 are arranged.

The machine housing 1 includes a metal outer frame 10 and a decorativecover 11, and as a whole is formed in a substantially box-like shape.The outer frame 10 constitutes a frame of the machine housing 1, and thedecorative cover 11 is fixed to the outer frame 10 in a manner ofcovering the outer frame 10 from the outside. It should be noted that,for the convenience of explanation, in FIG. 1, the outer frame 10 isshown by a dotted line, and at least one part of the decorative cover 11is shown by a dash-dot line (FIG. 6, which is to be mentioned later,also relates to the above case).

The outer frame 10 integrally includes a total of four vertical columns12 that are arranged one by one at four corners of the machine housing 1in plan view from the upper side Z1 and extend in the up-down directionZ. An upper horizontal strut 13 is bridged between upper ends of twovertical columns 12 that are arranged one after another in thefront-rear direction and extends in the front-rear direction Y, and alower horizontal strut 14 is bridged between lower ends of the twovertical columns 12 that are arranged one after another in thefront-rear direction and extends in the front-rear direction Y. Althoughnot shown, the outer frame 10 further includes a horizontal strut thatis bridged between the two vertical columns 12 that are arranged side byside in the left-right direction and extends in the left-right directionX.

Each of the vertical columns 12 does not necessarily have to extendstraight in the up-down direction Z, and may be bent or curved into acrank shape midway. Similarly, the upper horizontal strut 13 and thelower horizontal strut 14 do not necessarily extend linearly in thefront-rear direction Y, and may be bent or curved in the crank shapemidway. In the present embodiment, each of the pair of left and rightupper struts 13 includes a front portion 13A extending from the upperend of the vertical column 12 in the front side Y1 to the rear side Y2,a middle portion 13B extending from the rear end of the front portion13A to the upper side Z1, and a rear portion 13C extending from theupper end of the middle portion 13B to the rear side and connected tothe upper end of the vertical column 12 of the rear side Y2, and as awhole is configured in a shape of a crank.

The decorative cover 11 is formed in a shape of a plate, and covers theouter frame 10 at least from the left side X1, the right side X2, thefront side Y1, the back side Y2 and the upper side Z1. A portion of thedecorative cover 11 that covers the outer frame 10 from the upper sideZ1 is provided thereon with an entrance (not shown) for taking thelaundry into the washing machine and taking the laundry out of thewashing machine 100.

The outer tub 3 is, for example, made of resin, and has a bottomedcylindrical shape. The outer tub 3 is disposed inside the outer frame10, and water can be stored inside the outer tub 3. The outer tub 3 hasa substantially cylindrical circumferential wall 15 arranged in theup-down direction Z and a disc-shaped bottom wall 16 that closes ahollow portion of the circumferential wall 15 from the lower side Z2.The circumferential wall 15 is provided therein with an opening 15Asurrounded by an upper end edge of the circumferential wall. The opening15A is located just below the above-described entrance (not shown) ofthe decorative cover 11 so that the hollow portion of thecircumferential wall 15 communicates with the entrance.

A plurality of ribs 17 is formed on the outer peripheral surface of thecircumferential wall 15 to protrude toward the radial outer side R ofthe circumferential wall 15 for reinforcing the circumferential wall 15.The ribs 17 include a longitudinal rib 17A that extends in the up-downdirection and a horizontal rib 17B that extends in the peripheraldirection S of the outer tub 3. Receiving portions 18 are provided atthe lower ends of two longitudinal ribs 17A adjacent in thecircumferential direction S. Four receiving portions 18 are integrallyprovided at the lower end portion of the outer peripheral surface of thecircumferential wall 15 in a manner of being arranged one by one at fourcorners of the machine housing 1 in a plan view. The two receivingportions 18 located at the front side Y1 are referred to as frontreceiving portions 18A, and the remaining two receiving portions 18located at the rear side Y2 are referred to as rear receiving portions18B. The two front receiving portions 18A are arranged closer to thelower side Z2 than the front portion 13A of the upper horizontal strut13 and are spaced apart in the left-right direction. The two rearreceiving portions 18B are arranged closer to the lower side Z2 than therear portion 13C of the upper horizontal strut 13 and are spaced apartin the left-right direction.

Each receiving portion 18 integrally includes a plate-shaped baseportion 19 that is bridged between two adjacent longitudinal ribs 17Aand is curved in a manner of bulging to the outer side R radially, and adome-shaped engagement portion 20 that bulges from an upper end of thebase portion 19A toward the upper side Z1. The space enclosed by thelower ends of two adjacent longitudinal ribs 17A, the receiving portion18 provided over these longitudinal ribs 17A, the engagement portion 20at the upper end of the receiving portion 18 and the outer peripheralsurface of the circumferential wall 15 is called an accommodation space21. The accommodation space 21 is a recess that is recessed toward theupper side Z1 and faces the engagement portion 20 and is exposed fromthe lower end of the base portion 19 toward the lower side Z2. Thereceiving portion 18 is formed with a through hole 18C that penetratesthe upper end of the engagement portion 20 in the up-down direction Zand a slit 18D that extends continuously from the through hole 18C tothe lower side Z2 and bisects the entire receiving portion 18 in thecircumferential direction S. The through hole 18C and the slit 18D arein a state of communicating with the accommodation space 21.

The lower surface of the bottom wall 16 is provided with a plurality ofribs 22 protruding toward the lower side Z2 and reinforcing the bottomwall 16, a drain 23 for discharging the water stored in the outer tub 3and the like.

The inner tub 4 shown by the two-dot chain line in FIG. 1 is made of,for example, metal, and is formed in a bottomed cylindrical shapesmaller than the outer tub 3 by a loop, and is housed coaxially in theouter tub 3. The inner tub 4 can house the laundry inward. An opening 4Athat communicates with the opening 15A of the outer tub 3 fromimmediately below is formed on the upper surface of the inner tub 4. Auser of the washing machine 100 puts the laundry into the washingmachine and takes them out of the washing machine via theabove-described entrance (not shown) of the decorative cover 11, theopening 15A and the opening 4A. A plurality of through holes (not shown)is formed in the inner tub 4 so that the water in the outer tub 3 cantravel between the outer tub 3 and the inner tub 4 via the throughholes. Therefore, the water level in the outer tub 3 is the same as thewater level in the tub 4. At a portion of the bottom wall of the innertub 4 that coincides with the center of the inner tub 4, a rotationshaft 4B protruding toward the lower side Z2 is disposed. The rotationshaft 4B is rotatably supported by the bottom wall 16 of the outer tub3. Therefore, the inner tub 4 is rotatable around the rotation shaft 4B.

The motor 5 is an electric motor such as a frequency inverter motor. Themotor 5 is fixed to the bottom wall 16 of the outer tub 3 from the lowerside Z2. The motor 5 has an output shaft (not shown) that protrudestoward the upper side Z1. The transmission mechanism 6 is interposedbetween the output shaft of the motor 5 and the rotation shaft 4B of theinner tub 4. As the transmission mechanism 6, a known one may be used.The transmission mechanism 6 transmits the driving force outputted bythe motor 5 from the output shaft to the rotation shaft 4B. As a result,the inner tub 4 rotates. In particular, in the dewatering process, theinner tub 4 is rotated at a high speed in order to cause centrifugalforce to act on the laundry to effectively dewater the laundry. Itshould be noted that a pulsator (not shown) that rotates to stir thestored laundry is provided in the inner tub 4, and the driving force ofthe motor 5 is transmitted from the transmission mechanism 6 to thepulsator.

The supporting member 7 is a member formed in a rod shape, which is alsoreferred to as a hanging rod, and is disposed in the machine housing 1in in a state of being elongated vertically. There are four supportingmembers 7, which are provided at the four corners of the machine housing1 one by one. Of the four supporting members 7, the pair of left andright supporting members 7 at the front side Y1 is referred to as frontsupporting members 7A, and another pair of left and right supportingmembers 7 at the rear side Y2 is referred to as rear supporting members7B. FIG. 1 and FIGS. 3 and 6 to be mentioned later show the frontsupporting member 7A and the rear supporting member 7B located at theleft side X1 one by one, and the front supporting member 7A and the rearsupporting member 7B located at the right side X2 are not illustrated.However, the pair of right and left front supporting members 7A overlapseach other when viewed in the left-right direction X, and the pair ofleft and right rear supporting members 7B overlaps each other whenviewed from the left-right direction X.

A friction damper can be used as an example of the supporting member 7.Of course, other well-known dampers, such as the hydraulic damper, canbe used as the supporting member 7. When the supporting member 7 is afriction damper, the supporting member 7 includes a rod 28 that extendsupward and downward in an elongated and linear shape and a hollowhousing 29 that houses the lower end of the rod 28. Referring to FIG. 2,which is a schematic longitudinal sectional view of the main portion andthe peripheral portion of the supporting member 7, the supporting member7 includes a disk-shaped damper member 30 connected to the lower end ofthe rod 28 in the housing 29 and an urging member 31 such as a coilspring, provided in the body 29. The rod 28 is movable relative to thehousing 29, and by this relative movement, the entire supporting member7 can expand and contract. In addition, since the urging member 31 urgesthe damper member 30 toward the lower side Z2 within the housing 29, thesupporting member 7, as a whole, is elastically extensible.

Referring to FIG. 3, which is a schematic left view of the main portionof the washing machine 100, in conjunction with the rod 28, a pair ofleft and right upper horizontal struts 13 of the outer frame 10 isprovided with one connection portion 32 at the front portion 13A and oneconnection portion 32 at the rear portion 13C (see FIG. 1). In otherwords, there are four connection portions 32 in total. Each of theconnection portions 32 is formed in a thin metallic plate shape in theup-down direction Z. The connection portion 32 may be providedintegrally with the upper horizontal strut 13 or may be fixed to theupper horizontal strut 13 with screws or the like as a separate member.The connection portion 32 provided on the upper horizontal strut 13 atthe left side X1 is configured in a manner of protruding to the rightside X2 toward the washing tub 2 from this upper horizontal strut 13.The connection portion 32 (not shown) provided on the upper horizontalstrut 13 at the right side X2 is configured in a manner of protruding tothe left side X1 toward the washing tub 2 from this upper horizontalstrut 13. In each of the upper horizontal strut 13, the connectionportion 32 provided at the front portion 13A is referred to as a frontside connection portion 32A, and the connection portion 32 provided atthe rear portion 13C is referred to as a rear side connection portion32B (see FIG. 1). Each of the connection portions 32 is formed with athrough hole 32C that runs through the connection portion 32 in theup-down direction Z. An inner peripheral surface 32D defining thethrough hole 32C in the connection portion 32 is formed into a sphericalshape that becomes narrower toward the lower side Z2.

At the upper end of the rod 28, a hemispherical upper engagement portion28A bulging toward the lower side Z2 is provided. The upper engagementportion 28A of each of the front supporting members 7A is fitted fromthe upper side Z1 into the through hole 32C of the front side connectionportion 32A located at the same position in the left-right direction Xso as to be in a state of engaging with the front side connectionportion 32A from the upper side Z1. The upper engagement portion 28A ofeach of the rear supporting members 7B is fitted from the upper side Z1into the through hole 32C of the rear side connection portion 32Blocated at the same position in the left-right direction X so as to bein a state of engaging with the rear side connection portion 32A fromthe upper side Z1. Each of the upper engagement portions 28A is in astate of being in spherical contact with the inner peripheral surface32D that defines the through hole 32C in the connection portion 32.

The housing 29 is formed in a substantially cylindrical shape whose longedge is in the longitudinal direction of the rod 28. The upper endportion of the housing 29, as the lower engagement portion 29A, isformed as a hemispherical shape bulging toward the upper side Z1. Therod 28 is in a state of vertically penetrating the upper end 29B of thelower engagement portion 29A and protruding toward the upper side Z1.The lower engagement portion 29A of each of the front supporting members7A is fitted from the lower side Z2 into the accommodation space 21 ofthe front receiving portion 18A at the same position in the left-rightdirection X so as to be in a state of engaging with the engagementportion 20 of the front receiving portion 18A from the lower side Z2.The lower engagement portion 29A of each of the rear supporting members7B is fitted from the lower side Z2 into the accommodation space 21 ofthe rear receiving portion 18B located at the same position in theleft-right direction X so as to be in a state of engaging with theengagement portion 20 of the rear receiving portion 18B from the lowerside Z2. In this way, the four receiving portions 18 are mounted one byone to the lower engagement portions 29A located at the lower portion ofeach of the supporting members 7. It should be noted that when the lowerengagement portion 29A is fitted into the accommodation space 21, therod 28 passes through the slit 18D of the receiving portion 18.

At each of the supporting members 7, the lower engagement portion 29A isin spherical contact with the inner peripheral surface 20A (see FIG. 2)where the accommodation space 21 is defined in the engagement portion20, and the rod 28 is in the state of protruding to the upper side Z1from the through hole 18C of the upper end of the receiving portion 18.The rod 28 may be disposed to extend vertically in the up-down directionZ or may be disposed to be inclined towards the left-right direction Xand the front-back direction Y with respect to the up-down direction Z.In the present embodiment, the rod 28 of the front supporting member 7Ais obliquely arranged in such a way that as the rod 28 goes to the upperside Z1, the rod 28 is inclined more towards the front side Y1, and therod 28 of the rear supporting member 7B is obliquely arranged in such away that as the rod 28 goes to the upper side Z1, the rod 28 is inclinedmore towards the rear side Y2.

Each of the supporting members 7 is in a state of being suspended fromthe connection portion 32 of the upper horizontal strut 13 of the outerframe 10 (see FIG. 1). The lower engagement portion 29A of the housing29 located at the lower end portion of the supporting member 7 isconnected to the outer tub 3 of the washing tub 2 by the receivingportion 18. Since each supporting member 7 is elastically extensible andcontractible, the four supporting members 7 are in a state ofelastically supporting the washing tub 2, the motor 5 secured to theouter tub 3 and the transmission mechanism 6 (see also FIG. 1).Therefore, the vibration of the washing tub 2 generated along with therotation of the inner tub 4 during the washing operation is preventedfrom being transmitted to the machine housing 1 through the connectionportion 32.

In addition, for each of the supporting members 7, since the dampermember 30 moves together with the lower end portion of the rod 28 whenthe supporting member 7 expands and contracts, and rubs the innerperipheral surface 29C (see FIG. 2) of the housing 29, a frictionalforce is generated between the damper member 30 and the inner peripheralsurface 29C of the housing 29. With this frictional force, the vibrationgenerated by the washing tub 2 is reduced. As described above, each ofthe supporting members 7 is in a state where the upper engagementportion 28A is in spherical contact with the connection portion 32 andthe lower engagement portion 29A is in spherical contact with theengagement portion 20 of the receiving portion 18. Therefore, theinclination of the supporting member 7 with respect to the up-downdirection Z is freely changed in such a way that the force caused by thevibration of the washing tub 2 does not act on the supporting member 7and the machine housing 1.

The four receiving portions 18 are arranged at the same height. Inparticular, the through holes 18C of the four receiving portions 18 arelocated at the same position in the up-down direction Z, respectively.Therefore, the housings 29 of the four supporting members 7, which arefitted into the accommodation space 21 of the receiving portion 18 fromthe lower side Z2, are arranged at the same position in the verticaldirection Z. Specifically, the upper ends 29B of the lower engagementportions 29A of the housings 29 of the four supporting members 7 thatare exposed from the through holes 18C are arranged at the same positionin the up-down direction Z.

On the other hand, among the four connection portions 32 where the upperhorizontal struts 13 of the machine housing 1 are engaged with the upperside engagement portions 28A of the engagement supporting members 7, thefront connection portion 32A provided at the front portion 13A islocated at a position that is lower than the rear connection portion32B. This rear connection portion 32B is provided at the rear portion13C (refer to FIG. 1) located at a position higher than that of thefront portion 13A. In this case, among the four supporting members 7, apair of front supporting members 7A having the upper engagement portions28 that are engaged with the front connection portions 32A has the samelength, and the other pair of rear supporting members 7B having theupper engagement portions 28A that are engaged with the rear connectionportions 32B has the same length. However, the length of the pair offront supporting members 7A and the length of the pair of rearsupporting members 7B are different. Strictly speaking, the frontsupporting member 7A is shorter than the rear supporting member 7B. Itshould be noted that, in one example, the length of the supportingmember 7 refers to a length of the line segment L that connects theportion 28B of the upper engagement portion 28A that coincides with thelower surface of the connection portion 32 to the upper end 29B of thelower engagement portion 29A and extends along the rod 28 when theoperation of the machine housing 100 is stopped. The length of the linesegment L is also the portion of a range of each of the supportingmembers 7 from the receiving portion 18 to the connection portion 32. Inother words, the length of the line segment L refers to a length of aportion of the supporting member 7 positively contributing to reducevibrations. Of course, as another example, the total length of the rod28 and the total length of the supporting member 7 may be defined as thelength of the supporting member 7.

FIG. 4 is a diagram showing a relationship between an amplitude of thevibration of the outer tub 3 of the washing tub 2 generated along withthe rotation of the inner tub 4 during the dewatering process and alength difference between a front supporting member 7A and a rearsupporting member 7B. FIG. 5 is a diagram showing a relationship betweenan amplitude of the vibration of the outer tub 3 generated along withthe termination of the rotation of the inner tub 4 at the end of thedewatering process and a length difference between the front supportingmember 7A and the rear supporting member 7B. In FIGS. 4 and 5, thehorizontal axis represents the length difference between the frontsupporting member 7A and the rear supporting member 7B when the frontsupporting member 7A is shorter than the rear supporting member 7B. Onthe other hand, the longitudinal axis of FIG. 4 represents the amplitudeof the vibration of the outer tub 3 generated during the rotation of theinner tub 4 in the dehydration, and the longitudinal axis of FIG. 5represents the amplitude of the vibration of the outer tub 3 generatedat the termination of rotation of the inner tub 4 when a braking isapplied along with the termination of the dewatering process. The unitof the length difference and the amplitude is, for example, mm.

The braking to the rotation of the inner tub 4 can be realized in amanner in which a control portion (not shown) provided in the washingmachine 100 controls a duty ratio to cause a rapid stop of the rotationof the motor 5 or in a manner in which a braking device (not shown) isadditionally provided and the control portion is used to cause thebraking device to operate such that the rotation of the motor 5 isstopped rapidly.

When a structure in which the four receiving portions 18 receiving thelower end portions of the supporting members 7 are arranged at the sameheight is used, as shown in FIG. 4, even if the length differencebetween the front supporting member 7A and the rear supporting member 7Bbecomes larger, the amplitude of the vibration of the outer tub 3 duringthe rotation of the inner tub 4 in the dewatering process is almostunchanged. On the other hand, as shown in FIG. 5, when the lengthdifference between the front supporting member 7A and the rearsupporting member 7B becomes larger, the amplitude of the vibration ofthe outer tub 3 generated when the rotation of the inner tub 4 isstopped due to the braking becomes smaller. In other words, it isconsidered that the vibration of the outer tub 3 due to the stop of therotation of the inner tub 4 is effectively reduced because of thedifference in length between the front supporting member 7A and the rearsupporting member 7B.

Therefore, when a structure in which the length of the pair of frontsupporting members 7A and the length of the pair of rear supportingmembers 7B are different and the four receiving portions 18 are arrangedin the same height position is adopted, even if a braking is applied tothe rotation of the inner tub 4 for stopping the dewatering process whenthe inner tub 4 is rotating during the dewatering process, the vibrationof the outer tub 3 can be effectively suppressed by the four supportingmembers 7. This can prevent the outer tub 3 of the washing tub 2 insidethe machine housing 1 from vibrating and colliding with the machinehousing 1.

FIG. 6 is a left view of a washing machine in a modified example. InFIG. 6, the same parts as those already described in FIGS. 1 to 3 aredenoted by the same reference numerals, and description of these partswill be omitted. In the washing machine 100 already described withreference to FIGS. 1 to 3, the washing tub 2 is always arrangedvertically. However, the washing machine 100 according to the modifiedexample shown in FIG. 6 can change the posture of the washing tub 2.

Specifically, the washing machine 100 according to the modified examplefurther includes a supporting frame 50, a rotation portion 51, a lockrelease mechanism 52 and a driving mechanism 53.

The supporting frame 50 includes a pair of left and right side plates 54and a bridge member (not shown) that is bridged between the pair of sideplates 54. In FIG. 6, only the side plate 54 at the left side X1 isillustrated. Each of the side plates 54 is formed into a substantiallyrectangular shape when viewed in the left-right direction X, and it thinin the left-right direction X. A washing tub 2 is disposed between thepair of side plates 54.

A position of the right side and a position of the left side of theouter tub 3 of the washing tub 2, which are at the same position whenviewed from the left-right direction X, each is provided with a metallicrotation shaft 55 protruding outward in the left-right direction X. Therotation shaft 55 of the outer tub 3 protruding towards the left side X1penetrates the side plate 54 at the left side X1, and is rotatablysupported by the side plate 54 at the left side X1 via a bearing (notshown). The rotation shaft 55 of the outer tub 3 (not shown) protrudingtowards the right side X2 penetrates the side plate 54 of the right sideX2, and is rotatably supported by the side plate 54 of the right side X2via a bearing (not shown). Accordingly, the washing tub 2 having theouter tub 3 and the inner tub 4 (not shown) is supported by thesupporting frame 50 and is rotatable around the rotation shaft 55 in amanner of crossing with the up-down direction Z. Specifically, with therotation of the washing tub 2, a central axis J of the outer tub 3 andthe inner tub 4 is inclined towards the front-back direction Y withrespect to the up-down direction Z. The rotation direction of thewashing tub 2 is referred to as the direction of rotation K.

An intersection angle of an imaginary reference axis M extending in theup-down direction Z and the central axis J which is an acute angle is arotation angle θ of the washing tub 2 with respect to the reference axisM. The smaller the rotation angle θ is, the closer the washing tub 2 isto the upright posture. The larger the rotation angle θ is, the more thewashing tub 2 is inclined towards the front side Y1 in such a way thatthe opening 15A of the outer tub 3 faces the front side Y1. The rotationangle θ can be changed be changed in five stages of, for example, 5degrees, 15 degrees, 30 degrees, 45 degrees and 60 degrees. The rotationangle θ in FIG. 6 is 60 degrees. In FIG. 6, the moving track of the endsurface on the opening 15A side of the outer tub 3 when the washing tub2 is rotated between 5 degrees and 60 degrees is illustrated by atwo-dot chain line.

As an example of the application of the washing machine 100 in themodified example, when the laundry are thrown into the washing tub 2 atthe start of the washing operation, the rotation angle θ is set to be 45degrees so that the laundry can be easily introduced. It is noted that,in the machine housing 1 of the washing machine 100 according to themodified example, a connection surface 1C that connects the frontsurface 1A and the upper surface 1B and descends towards the front sideY1 is provided, and the above-described entrance (not shown) is formedacross the front surface 1A and the connection surface 1C. In addition,after the laundry is put in, when detecting the load amount of thelaundry or supplying water to the outer tub 3, the rotation angle θ isset to be 5 degrees. Then, during the washing process and the rinsingprocess, the rotation angle θ is set to be varied between 5 degrees and60 degrees in order to facilitate the alternation of the positions ofthe laundry in the inner tub 4 for effective washing and rinsing.

An opening 54A that penetrates the side plate 54 in the left-rightdirection X is formed in a region of the side plate 54 of the left sideX1 closer to the lower side Z2 than the rotation shaft 55 is. Theopening 54A is formed in a substantially rectangular shape elongated inthe front-rear direction Y.

The rotation portion 51 is a metal plate which is thin in the left-rightdirection X and is formed in a substantially fan-like shape bulging tothe front side Y1 as viewed from the left-right direction X. Therotation portion 51 has an outer peripheral edge 51A formed in an arcshape along the rotation direction K and bulging toward the front sideY1. A through hole 51B that penetrates the rotation portion 51 in theleft-right direction X is formed at a position of the rotation portion51 in accordance with the center of curvature of the outer peripheraledge 51A. A plurality of recesses 51C are formed on the outer peripheraledge 51A. There are five recesses in this embodiment. These recesses 51Care recessed toward the through-hole 51B and penetrate the rotationportion 51 in the left-right direction X, and are arranged side by sidein the rotation direction K. The intervals between the adjacent recesses51C may be constant or may be different depending on the position of therotation portion 51. In the present embodiment, corresponding to therotation angle θ which is set to 5 degrees, 15 degrees, 30 degrees, 45degrees, and 60 degrees, in the rotation portion 51 in the attitude ofFIG. 1, the two recesses 51C at the most rear side Y2 and the adjacentposition thereof are spaced apart by 10 degrees in the rotationdirection K (the circumferential direction with the through hole 51B asthe center), and the intervals between the other adjacent recesses 51Care set to be 15 degrees uniformly.

The rotation portion 51 is disposed to be closer to the left side X1than the side plate 54 is. The rotation shaft 55 protruding to the leftside X1 at the outer tub 3 and running through the side plate 54 at theleft side X1 is inserted into the through hole 51B of the rotationportion 51, and is fixed to the rotation portion 51. Thus, the rotationportion 51 is connected to the outer tub 3 the rotation shaft 55, suchthat the rotation portion 51 may rotate integrally with the outer tub 3.

The rotation portion 51 in the attitude of FIG. 6 is integrally providedtowards the lower side Z2, at the rear end of the outer peripheral edge51A, specifically, with an extension portion 51D protruding outward inthe radial direction T of the rotation portion 51 with the through hole51B as the center. The extension portion 51D is formed with a guide hole51E that is long in the radial direction T and runs through theextension portion 51D in the left-right direction X. The guide hole 51Eand the opening 54A of the side plate 54 at the left side X1 are locatedat the same position in the up-down direction Z, and always faces theopening 54A from the left side X1.

The lock release mechanism 52 is fixed to the left surface of the sideplate 54 at the left side X1. The lock release mechanism 52 includes amain body portion 56 provided with an actuator (not shown) composed of asolenoid or the like, and a lock portion 57 formed in a convex shapeprotruding toward the back side Y2. The lock portion 57 is supported bythe main body portion 56 in a way that the lock portion 57 is slideablein the front-back direction Y. The actuation of the actuator of the mainbody 56 causes the lock portion 57 to slide between an entry positionwhere the lock portion 57 enters toward the rearmost side Y2 and aretracting position where the lock portion 57 is retracted toward theforemost side Y1. The lock portion 57 in FIG. 6 is located at the entryposition in a state of being embedded in the recess 51C provided at thesame position in the rotation direction K. Thus, the rotations of therotation portion 51 and the washing tub 2 are locked. In this state,when the lock portion 57 is retreated to the retracting position, thelock portion 57 is disengaged from the recess 51C, and thus, the lockingof the rotation portion 51 and the washing tub 2 is released.

The driving mechanism 53 includes a frame 58, a pair of receivingportions 59, a threaded shaft 60, a motor 61, a coupling 62, a nutmember 63 and a sensor 64.

The frame 58 is formed by bending a metal plate into, for example, acrank shape, and the frame 58 is fixed to the side plate 54 from theright side X2 so as to cover the opening 54A of the side plate 54 at theleft side X1 from the right side X2. The pair of receiving portions 59is fixed to the frame 58 in a state of being spaced apart from eachother in the front-back direction Y and protruding from the frame 58 tothe left side X1. The threaded shaft 60 is formed in a columnar shapeelongated in the front-rear direction Y, and is provided with a helicalthread 60A extending in a spiral shape formed over substantially theentire outer peripheral surface thereof. The threaded shaft 60 isrotatably supported at two ends by bearing (not shown) provided on thepair of front and rear receiving portions 59.

The motor 61 is a general electric motor, and has an output shaft 65that protrudes to the rear side Y2 and is arranged coaxially with thethreaded shaft 60. The front end of the threaded shaft 60 and the outputshaft 65 are coupled to each other by a coupling 62 such that thethreaded shaft 60 and the output shaft 65 can be integrally rotated.Therefore, when the motor 61 is driven so that the output shaft 65 isrotated, the threaded shaft 60 rotates integrally with the output shaft65. The nut member 63 has an annular nut formed with thread (not shown)extending in a spiral shape at an inner peripheral surface thereof andis externally fitted to the threaded shaft 60 in a such a way that thethread is threadedly connected to the thread 60A of the threaded shaft60. When the threaded shaft 60 is rotated by the driving of the motor61, the nut member 63, as a whole, moves in the axial direction of thethreaded shaft 60, i.e. the front-back direction Y, along with therotation of the screw shaft 60. The nut member 63 is secured with aconnection pin 66 which is inserted into the extension portion 51D ofthe rotation portion 51, such that the nut member 63 is connected to therotation portion 51 via the connection pin 66. Therefore, when the nutmember 63 moves in the front-rear direction Y along with the rotation ofthe threaded shaft 60, the rotation portion 51 is pulled by the nutmember 63 in the front-rear direction Y, thereby rotating with thewashing tub 2.

The sensor 64 is a sensor that detects the rotation angle θ of thewashing tub 2 based on the position of the nut member 63 in thefront-rear direction Y. As the sensor 64, an optical sensor such as aphoto sensor may be used. In this case, the number of the sensors 64 isset to be the same as the number of the recesses 51C of the rotationportion 51, and the sensors 54 are fixed to the frame 58 in a state ofbeing aligned in the front-rear direction Y. Each sensor 64 is formedwith a groove 64A penetrating the sensor 64 in the front-rear directionY, and the sensor 64 is in a state that the detection light traversesthe groove 64A in the up-down direction Z. The nut member 63 is providedwith a rod-shaped detected portion 63A, which is referred to as alimiting portion. When the rotation angle θ is set to be one of 5degrees, 15 degrees, 30 degrees, 45 degrees and 60 degrees, the detectedportion 63A is embedded in the groove 64A of one of the sensors 64 andshields the detection light of the groove 64A. Therefore, the fivesensors 64 collectively detect which one of 5 degrees, 15 degrees, 30degrees, 45 degrees and 60 degrees is the rotation angle θ.

In the washing machine 100 of the modified example, a pair of left andright longitudinal plates 71 protruding outward in the front-reardirection Y is provided on a front end edge and a rear end edge of eachside plate 54 of the supporting frame 50. One receiving portion 18 isprovided on the pair of longitudinal plates 71, and the receivingportion 18 is integrated with the longitudinal plates 71. Like the casein the above-described embodiment (see FIGS. 1 to 3), there are fourreceiving portions 18, which are arranged at the four corners of themachine housing 1 one by one when viewed from top. Among the fourreceiving portions 18, the two front receiving portions 18A are disposedcloser to the lower side Z2 than the front portion 13A of the upperhorizontal strut 13, and are spaced apart from each other in theleft-right direction, and the two rear receiving portions 18B aredisposed closer to the lower side Z2 than the rear portion 13C of theupper horizontal strut 13, and are spaced apart from each other in theleft-right direction.

The base portion 19 of the front receiving portion 18A is formed into acurved plate shape in a manner of being bridged between two longitudinalplates 71 which are provided at the front edges of the side plates 54and bulging toward the front side Y1. The base portion 19 of the rearreceiving portion 18B is formed into a curved plate shape in a manner ofbeing bridged between two longitudinal plates 71 which are provided atthe rear edges of the side plates 54 and bulging toward the rear sideY2. The accommodation space 21 is a space enclosed by the two adjacentlongitudinal plates 71, the base portions 19 and the engagement portion20.

In the washing machine 100 in the modified example, four supportingmembers 7 are arranged at four corners of the machine housing 1 one byone. In the washing machine 100 according to the modified example, asshown in FIG. 3, among the four supporting members 7A, the upperengagement portions 28A of the two front supporting members 7A are in astate of being engaged from the upper side A1 with the front connectionportions 32A that are provided at the same position in the left-rightdirection X, and the upper engagement portions 28A of the two rearsupporting members 7B are in a state of being engaged from the upperside Z1 with the rear side connection portions 32B that are provided atthe same position in the left-right direction X. The lower engagementportion 29A of each of the front supporting members 7A is fitted fromthe lower side Z2 into the accommodation space 21 of the front receivingportion 18A located at the same position in the left-right direction Xso as to be engaged with the engagement portion 20 of the frontconnection portion 32A from the lower side Z2. The lower engagementportion 29A of each of the rear supporting members 7B is fitted from thelower side Z2 into the accommodation space 21 of the rear receivingportion 18B located at the same position in the left and right directionX so as to be engaged with the engagement portion 20 of the rearconnection portion 32B from the lower side Z2. The lower engagementportion 29A is in a state of being spherical contact with the innerperipheral surface 20A (see FIG. 2) that defines the accommodation space21 in the engagement portion 20, and the rod 28 is in a state ofprotruding from the through hole 18C of the upper end of the receivingportion 18 to the upper side Z1.

Each of the supporting members 7 is in a state of being suspended fromthe connection portion 32 provided on the upper horizontal strut 13 ofthe outer frame 10. The four receiving portions 18 are mounted one byone to the lower engagement portions 29A located at a lower portion ofthe supporting members 7. Thus, as shown in FIG. 6, each of thesupporting members 7 is connected to the outer tub 3 of the washing tub2 via the side plate 54 of the supporting frame 50 through the receivingportion 18. Since each supporting member 7 is elastically extensible andretractable, the four supporting members 7 suspend the washing tub 2,the motor 5 and the transmission mechanism 6 (see FIG. 1) which arefixed to the outer tub 3, the supporting frame 50, the rotation portion51 and the lock release mechanism 52 for elastic support.

Similar to the washing machine 100 of the modified example in which thewashing tub 2 is rotatable as described above, all the receivingportions 18 for receiving the lower ends of the supporting members 7 arearranged at the same height position, and the length of the pair offront supporting members 7A is different from the length of the pair ofrear supporting members 7B. Strictly speaking, the front supportingmember 7A is shorter than the rear supporting member 7B (see FIG. 3). Inthis case, as described with reference to FIGS. 4 and 5, since thevibration of the outer tub 3 is effectively suppressed by the foursupporting members 7, the vibration of the outer tub 3, that is, thevibration of the washing tub 2, and the collision with the machinehousing 1 can be prevented.

The present disclosure is not limited to the above-describedembodiments, and various changes may be made within the scope of theclaims.

For example, among the four supporting members 7, the pair of frontsupporting side members 7A is shorter than the pair of rear supportingmembers 7B. However, the pair of rear supporting members 7B may beshorter than the pair of front supporting members 7A. In addition, thefour supporting members 7 may be configured such that instead of thepair of supporting members 7 on the front side Y1 and the pair ofsupporting members 7 on the rear side Y2 being different in length, thepair of supporting members 7 on the left side X1 and the pair ofsupporting members 7 on the right side X2 are different in length.

What is claimed is:
 1. A washing machine, comprising: a machine housing,a washing tub having an inner tub which accommodates laundry and isrotatable and an outer tub for receiving the inner tub, and beingprovided inside the machine housing, four supporting members, which areconfigured to be in a shape of a rod suspended from the machine housingand elastically support the washing tub, and receiving portions, whichare mounted at the lower portion of each of the supporting membersrespectively to connect the supporting members to the washing tub,wherein all the receiving portions are provided at the same height, andamong the four supporting members, a length of a pair of supportingmembers and that of another pair of supporting members are different. 2.The washing machine according to claim 1, wherein the washing tub iscapable of rotating in a manner of crossing with a vertical direction.